In the drilling, completion, and production of oil and gas wells, it is common practice to work with formation pressure. There are various stages and conditions of an oil or gas well during which access to the inside of the well is required. In underbalanced drilling, drilling occurs without restricting pressure from the well bore. Completion is a stage during which the well is perforated by shooting holes in the casing, while well servicing occurs during workover operations. In all of these cases, when drilling, completion or workover operations are performed, it is necessary in order to prevent hydrocarbons from leaking to atmosphere, to provide a containment device to contain gas within the well bore. This containment is important at all times but more particularly during snubbing operations when tool strings or tubing is jacked into and out of the well while the well is live. During snubbing, a stripping device is required for containment of the hydrocarbons, and the well bore pressure. Some standard containment approaches include a Blow Out Preventer (BOP) or an annular preventer, which comprise a piston which squeezes rubber to seal mechanically and may sit above a BOP. These systems may also be rotating pressure control systems. The standard approaches have limits with respect to the size or diameter of tool string or tubing that can be stripped in and out of the containment device for access to the well bore. Often if tool strings or tubing are of widely differing diameters, multiple annular containment spools are required, increasing costs incurred by the purchase and maintenance of multiple devices, and delays and lost production time due to the need to fit a new spool or containment device which fits the new tool string or tubing. This is particularly the case when switching between different tool strings and tubing used in drilling and work over operations. Due to the limits of the ranges of tool string and tubing shaft sizes compatible with standard devices, safety also becomes an issue when the size of a tool string or tubing is not within the safe range of shaft sizes compatible with the containment device. Size of the containment device itself is also an issue as it is more desirable to have a closely configured hydraulic jacking system.
It would be desirable in drilling and snubbing operations for there to a be a single stripping and containment device which has a wide range of tool string or tubing size compatibility. This is desirable for safety reasons and for cost efficiency. It is also desirable to find a single device which can be used for well bore pressure containment during underbalanced drilling, completion and work over operations. It is also more desirable to implement a smaller device than standard existing ones.